The present invention relates to a tablet, particularly a pharmaceutical dosage form, containing an encapsulating agent comprising a modified starch which is prepared by enzymatic hydrolysis of a starch molecule after the preparation of a starch derivative containing a hydrophobic group or both a hydrophobic and a hydrophilic group.
U.S. Pat. Nos. 4,977,252 and 5,185,176 issued to Chiu disclose starch derivatives containing a hydrophobic or both a hydrophobic and a hydrophilic group which have been enzymatically degraded by exo-enzymes. These modified starches are useful as emulsifiers.
Compressed tablets are well-known, particularly in the pharmaceutical industry. Known methods of tabletting include direct compression and wet or dry granulation followed by compression. Tablet formulations characteristically should be free flowing, cohesive and lubricating. Sometimes, it is desired to encapsulate a component of the tablet and gelatin is considered as a standard encapsulating agent in many industries.
However, consumers may desire products which do not contain gelatin for a variety of reasons including dietary to meet strict Kosher, Halal or vegetarian standards. Many consumers also want to avoid bovine products because of the current scare over Bovine Spongiform Encephalopathy (Mad Cow Disease). Further, gelatin is an expensive excipient and its replacement is desirable to reduce the cost of the product.
It is known in the art that certain starches are excellent encapsulating agents. However, as starches are generally used as disintegrants, impeding compression and hardness of the tablet, starch encapsulating agents are not generally used in significant quantities in tablets. Hardness is necessary in a tablet as it provides resistance to chipping, abrasion, and breakage under conditions of storage, transportation, and handling prior to consumer consumption.
Other encapsulating agents are also known in the art such as gum arabic, dextrins, arabinogalactan, gum acacia, casein, carboxymethyl cellulose, tragacanth, karaya, sodium alginate, and tannin. However, none of these encapsulants allow for good compressibility while providing high load and retention of the active agent and oxidative resistance.
Surprisingly, it has now been discovered that the present invention which uses an encapsulating agent comprising a modified starch, prepared by enzymatically converting a starch after the preparation of a starch derivative containing a hydrophobic group or a hydrophobic and a hydrophilic group, allows similar compressibility characteristics and resultant hardness to gelatin in a tablet formulation. In addition, the starch may consistently allow for high load and retention of a variety of active agents as well as oxidation resistance.